Some agricultural harvesting heads (called “heads” or “headers” herein) include endless belt conveyors that receive cut crop material. These conveyors move the crop laterally with respect to the frame of the head. They may deposit the crop material on another conveyor mounted on the head, or they may deposit the cut crop material on the ground.
In some arrangements, the conveyors can be shifted from side to side on the frame of the head. In these arrangements a conveyor that is shifted is typically supported on a subframe that is movable with respect to the frame of the head. This movable subframe plus conveyor is commonly called a “deck”. The process of moving the deck from side to side is commonly called “shifting” the “deck”.
For each deck at least one motor is provided to recirculate the endless belt of that deck's conveyor around the deck thereby conveying cut crop material. For each deck at least a second motor is provided to shift the deck side to side on the frame of the head. These motors are typically hydraulic. They may be rotary motors or linear motors.
One problem with this arrangement is getting the conveyor decks to shift quickly and completely. Often hydraulic fluid is provided to the hydraulic motors in parallel, such that the hydraulic fluid is supplied to the motors to simultaneously shift the conveyor decks and run the conveyor belts. At times the conveyor decks do not receive enough hydraulic fluid to shift completely. As a result, the conveyor belts continue running before the decks are in position. This causes cut crop material to fall into gaps between the decks and onto the ground.
What is needed is a better system for operating the deck shift motors and the conveyor belt motors that causes the decks to shift completely and rapidly. It is an object of this invention to provide such a system.